Research On Self-energizing Power Source Of Air-core Reactor Wireless Monitoring Device

Air-core reactor is one of the important components of the substation operation part of the power systems.In the operation of the power grid,the reactor may not be processed in time because the internal temperature continues to be too high and exceeds the limit value,eventually resulting in a fire or explosion accident.If there is an accurate alarm when the temperature is higher than the limit value,an accident can be effectively avoided.Among the existing Air-core reactor monitoring methods,the online monitoring technology has problems such as the need for regular maintenance in the power supply,high costs,and inability to provide power for real-time monitoring.Aiming at the problem of the power supply in the online monitoring device,this paper conducts in-depth research from three aspects: the selection of the core shape of the power supply,the optimization of the core structure parameters,and the design of the rectifier circuit.This article is based on the structure of the Air-core reactor and the principle of electromagnetic induction,a scheme is proposed that utilizes the characteristics of internal magnetic leakage of the Air-core reactor during operation,places energy-receiving elements inside the reactor,and uses the induced voltage to provide power for the monitoring device.Comparative analysis of E-shaped iron core,I-shaped iron core,toroidal iron core with the same cross-sectional area and the same volume as the special-shaped iron core(X-shaped iron core)proposed in this paper.The calculation of the magnetic field analyzes the magnetic induction strength inside different shaped iron cores.On this basis,E-shaped and X-shaped iron cores with large magnetic flux are selected for further research.Compare the parameters such as the number of turns of the coil,the air gap,and the way the coil is wound.Through electromagnetic induction calculation and induced electromotive force pushback,use the finite element simulation to obtain the magnitude of the induced voltage and the transient waveform.Select the induced voltage under the same parameters The shape of the highest iron cores.Aiming at the problem that the harmonic component of the AC voltage induced by the self-capturing device is large,a DC output device is designed.According to the requirements of the monitoring terminal for power quality,a DC output circuit composed of bridge rectification,LC series filtering and LM7812,7805 voltage stabilizing element is designed to rectify the AC sinusoidal voltage output from the coil to the DC stable voltage available to the monitoring device.The simulation calculation using PSCAD software verified the effectiveness and stability of the rectifier circuit.Through field experiments,the prototype of the monitoring device was improved,and the thermistor selected by the monitoring device,the program design based on the DSP chip,and the Lo Ra wireless transmission device were tested and verified in the field.The experimental results show that the self-energizing power supply designed in this paper can provide continuous and stable power supply support for Air-core reactor monitoring devices.